Rock-drill.



Patented lune 4, 190|.

ROCK DRILL.

(Application filed Oct. 8, 1900.)

C. T. LITCHFIELD.

(No Model.)

, UNITED STATES PATENT OFFICE.

CHARLES TIFFANY Ll'lCllFIELD, OF SPOKANE, lVASl-IINGTON.

ROCK-DRILL.

SPECIFICATON forming part of Letters Patent No. 675,490, dated June 4,1901.

.aspiration and october s, 1900. senti No. 32,403. un man.)

Be it known that I, CHARLES TIFFANY LrroHrTEL'n, a citizen of the UnitedStates, residing at Spokane, in the county of Spokane and State ofWashington, have invented a certai new and useful Improvement in Rock-Drills, of which the following is a full, clear, and exact description.

This invention relates to the valve mechanism of rock-drills and other'pneumatic or Huid-pressure tools or apparatus.

The object of the invention is to provide mechanism whereby not only theforward movement, but the return movement to com plete the stroke, shallbe elfected by pressure automatically controlled.

In carrying out my invention I employ a reciprocating piston connectedwith a plunger, the two being separated by a diaphragm, whichpermanently divides the pressurechamber in which the piston moves fromthat in which the plunger moves, and within the medium connecting thepiston with the plnn` ger I employ a valve by which the ilow of theiluid or pressure agent is controlled and also by which the pressure istransferred from one side to the other ol the piston to el'l'ect theforward and backward movements to complete the stroke.

I have illustrated my invention as applied to one forni of rock-drill inwhich compressed air is used as the motive power; but I wish to beunderstood as not limiting my invention to rock-drills or otherapparatus employingr compressed air as the motive power.

lVith this explanation I will proceed now to describe my invention asapplied to a rockdrill. l. y

In the accompanying drawings, illustrating my invention, in the severalligurcs ol' which like parts are similarly designated, Figure l is alongitudinal sectional elevation showing the parts in the position theywill occupy at the end of the return movement. Fig. 2 is a similar Viewof oni y so much lof the appara-tu.-. as is necessary to show theposition of parts at the beginning ol` the -,forward movement. Fig. i isa View similar to Fig. 2, showing the parts at the end of the forwardmovement and in position to begin the return movement. Figs. 5, G, and 7are cross-sections of the cylinder, taken, respectively, in the planesof lines fi, 5, 6, and 7 of Fig. l.

The cylinder a is provided with the internal liners and c, which linersare separated by a diaphragm d, preferably composed of simi lar metallicshells having recessed adjacent faces, in which is arranged any suitablepacking, such as an elastic or compressible outer member and a metallicinner member, in one or more sections. The liner b is provided with thelongitudinal channel e, which communicates at one end with asupply-passage j for the introduction of compressed air, steam, or otherequivalent motive agent, and this passage extends to the diaphragm andcommunicates with the interior of the liner by means of a port y. Theliner c has spiral grooves or other exhaust-passages hin its innersurface. The ends of the cylinder are provided with heads t' and j,which in the case of a rock-drill provide bearings la and l for thefeed-screw m, which is arranged in a nut o of a supporting-bracket p,and the said feed-screw may be provided with any suitable means, suolias a crank-handle, as shown, for rotating it. The chamber formed in theliner b between the head 'i and the diaphragm receives the piston q, andthis piston has a longitudinal channel r extending through it andthroughout the length ol its rod r', which is of less diameter than thepiston-headpand this rod is connected with the plunger r2, which isarranged in the chamber in the liner c between the forward side oi' thediaphragm and the head j and made air or llnid tight therein by suitablepacking, as at r3.

The piston-rod is provided with the through ports fr near one end andith lateral ports T5 'r5 and through-ports 1 at or nearthe other end.W'ithin this hollow piston-rod is ar ranged a valve s, having alongitudinal bere sx extending from one end to near the other and atsuch closed end having a longitudinally-extended lateral port s', of alength sul'licient to uncover the ports T5, r, and lr?. The closed endof this valve projects into a chamber within the plnngerrzand is backedup by a-spring s2 in said chamber, which normally tends to throw thevalve to the left or rearward. The chamber in the plungerl whichcontains the spring has a longitudinal chan` the back or return movementof the stroke,

as shown in Fig. 1, the motor fluid is admitted through inlet f, channele, and port g into the space between the-forward side of the piston-headand the rear side of. the diaphragm and at the same time escapes throughports r and s' and bore 3X and the channel r to the rear of thepiston-head on one side of the diaphragm. The pressure being now whollyto the left or rear of the diaphragm serves to move the valve s forwardfrom the position Fig. 1 to the position Fig. 2, thus opening orts 14-and 77, thus admitting the pressure duid through the holler; valve andports T5 and lr7 into the chamber? the other or forward side of thediaphragm, and since the superficial area of pressure surface,comprising the rear face of the piston, the rear end of the plunger, andthe exposed surfaces of the valve, is greater than the supercial area ofthe forward end ot the piston it fol lows that the piston and itsadjuncts will be moved forwardly until the ports r4 enter the diaphragmand are closed thereby, and thereby further admission of air to the rearof the piston is prevented, and then the air acting by its expansiveforce will complete the forward movement until the plunger uncovers theexhaust-passages h, as lshown in Fig. 2. When this occurs, all of theair in the cylinder escapes excepting that which is confined in thechamber in the liner h between the 'for ward-face of the pistonhead andthe rear face of the diaphragm and air is admitted through channels s3and s4 to the forward solid end of the valve, and that pressure, to- Agether with they recoil of the'spring s2, is sufticient to shift thevalve to the left, asin Figs. 1 and 3, covering up the ports r4, whichhave been moved to the right of the diaphragm, and uncovering thethrough-ports T7 to exhaust the pressure in the rightehand chamber, sothat the piston and plunger are relieved from back pressure on thereturn movement. As soon as the ports r* are closed by the reaction ofthe valve the air-pressure in the inlet-chamber between the forward faceof the' piston-head and the rear face of the diaphragm, which pressureis constant, forces the piston to the left on the com pletion of thereturn movement. When the port is passed to the rear or left-hand sideof the diaphragm on the backwardI movement, Fig. l, air is ad.- mittedthrough said port and the hollow valve and hollow piston to the rear ofthe piston,

vnext forward movement.

and the first result is the return or forward movement of the valve, soas to uncover the ports r4 and close the portsr'l-fromthe outer air, andthus the parts are in position for the rIhe diaphragm being made ofsections with interposed packing material and being arranged between theliners and the liners being held in place by the heads of the outercylinder, lam enabled to insure a sufficient compression of the packingagainst the piston-rod to obtain at all'-l times a fluid-tight joint.

I do not limit my invention to the employment of liners, since' thevarious channels may be made in the body of the cylinder; but forstructural purposes and for purposes of re'- newal and repair l muchprefer to use the liners.

l. A. fluid-motor, having a cylinder, a dia' phragm dividing thecylinder into'two cham; bers one of which is, the inlet and the otherthe outlet for said cylinder, a piston arranged in the inlet-chamber anda plunger arranged in the outlet-chamber, a hollow piston-rod passingfluid-tight through the diaphragm..

and rigidly connecting the piston and plun ger, and having a series ofportsnear its opposite ends, and a valve arranged in said' hollow rodand provided with a longitudinal bore opening axially at one end andlaterally near the other end and cooperating with the several ports inthe hollow rod to control the admission and exhaustion of the motivefluid so as positively to eiect the movement of the piston in bothdirections, substantiallyas de scribed.

l. 2., A cylinder having a diaphragm dividing it into inlet and outletchambers, a piston in the former and a plunger in the `latterga hollowported rod passing Huid-tight through the diaphragm and connecting thepiston and plunger, and an axially-bored and laterallyported slide-valvearranged within said hollow rod and edperating with its ports,substantially as described.

3. A cylinder having a diaphragm, channeled liners arrangedwithinihec'ylinder and on opposite sides of said diaphragm and form'-ing inlet and outlet chambers respectively, a piston in theinlet-chamber and a plunger in the outlet-chamber, a tubular portedconnection for the piston' and the plunger, and a slide-valve arrangedin the tubular connection and bored longitudinally at one end and portedlaterally near the other end and co operating with the ports in the saidconnection, the plunger itself having pressure-inlets communicating withthe valve,substantially as described. r

et. A cylinder having a diaphragm dividing it into inlet and outletchambers, apiston in the former and a plunger in the latter, ahollowported rod passing duid-tight through the diaphragm and plunger, andanaxially-bored and laterallyported slide-valve arranged within saidholloo IIO

connecting the pistou and low rod and coperating with its ports, thediaphrasgrnA itself periodically serving to cub oi the admission of themotive agent to the rear of the piston, substantially as'described. Y

5. Acylinder havinga. diaphragm dividing it; into inlet and outletchambers, liners arranged in said chambers and having channels openinginto the chambers and communicating respectively with a source of supplyof power and the external air, on'opposite sides of the diaphragm, apiston in the inlet-chamber and a plunger in the outlet-chamber, andvalve mechanism for controlling -the admission and exhaustion of thepower agent, sub- I5' stantially as described.

6. A cylinder having a compressible diaphragm dividing it into twochambers, liners arranged in said chambers and abutting against thediaphragm, and cylinder-'heads 2o holding the'liners nslplace,substantially as described. y 4 In testimony whereof I have hereuntoset. my hand this 1st day of October, A. D. 1900.-

- CHARLES TIFFANY LITOIIFIELD.

Witnesses:

B. LICHTY,

DAN L. WEAVER.

Itis hereby ceried that in lLetters Patent'No. 675,490, grantedunei,*1901, upon lcheapplieetaion of Charles Tiffany Litchfield, of Spokane,Washington, for an imprese? meub in Rock-Drills, an error appears in theprinted'specication requiring correc-v tion, as follows: In line 34.,page 1, after the .word r0ck-drl1s,a,l comma and the words or torock-drills should be inserted; and that the said Letters Patent sholdbe read with this correction therein thai; the same mary conform to therecord of the case in the Patent; Oice. I n i l Signed, countersigned,and sea? `d this 18th day of June, A. D., 1901.

[sEAL] F. L. CAMPBELL,

Assistant Secretary ofthe Litcror.

Countersigned 1F. I. ALLEN,

Chmmissoner of Paients.

